GB/T 9074.11-1988
Cross recessed hexagon bolt with indentation and plain washer assemblies
GB/T 9074.12-1988
Cross recessed hexagon head bolt with indentation and spring washer assemblies
GB/T 9074.13-1988
Cross recessed hexagon head bolt with indentation , spring and plain washer assemblies
GB/T 9074.13G-1988
Cross recessed hexagon head bolt with indentation , spring and large plain washer assemblies